Field of the Invention
This invention broadly relates to closure fastners, and more particularly to a door latch bolt locking device for use with a door having a door-knob controlled retractable latch bolt provided with a kerf or groove for operation with the locking device of this invention.
Because key-controlled knob-actuated latch bolts are subject to comparitively easy jimmying, many and varied safety devices and guards have been devised and offered for use. Although many of these prior art adaptations well serve the purposes for which they have been perfected and used, they, for the most part, require extra keys and are often difficult to install and are consequently expensive. There has long existed a need for a readily applicable device which is simple to operate and not visually and physically obtrusive.
Accordingly, the primary object of this invention is to provide a door latch bolt locking device which can be simply attached to a door and which is physically and visually unobtrusive.
Another object of this invention is to provide a door latch bolt locking device which is adapted to positively prevent the retraction of the bolt from its door-locking position.
Yet another object of this invention is to provide a door latch bolt locking device which can only be operated from the inside of the door and is provided with means to positively lock the bolt and to make it non-tamperable with thin plastic cards or the like.
Other objects and advantages of the present invention will become apparent from the following description and claims, the novelty of the invention consisting in the features of construction, the combination of parts, the novel interaction of the parts, all of which are more particularly described in the following description and the accompanying drawings wherein: